nsz Git - musl/blob - src/multibyte/mbsrtowcs.c

   1 /*
   2  * This code was written by Rich Felker in 2010; no copyright is claimed.
   3  * This code is in the public domain. Attribution is appreciated but
   4  * unnecessary.
   5  */
   6
   7 #include <stdlib.h>
   8 #include <inttypes.h>
   9 #include <wchar.h>
  10 #include <errno.h>
  11
  12 #include "internal.h"
  13
  14 size_t mbsrtowcs(wchar_t *restrict ws, const char **restrict src, size_t wn, mbstate_t *restrict st)
  15 {
  16         const unsigned char *s = (const void *)*src;
  17         size_t wn0 = wn;
  18         unsigned c = 0;
  19
  20         if (st && (c = *(unsigned *)st)) {
  21                 if (ws) {
  22                         *(unsigned *)st = 0;
  23                         goto resume;
  24                 } else {
  25                         goto resume0;
  26                 }
  27         }
  28
  29         if (!ws) for (;;) {
  30                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  31                         while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  32                                 s += 4;
  33                                 wn -= 4;
  34                         }
  35                 }
  36                 if (*s-1u < 0x7f) {
  37                         s++;
  38                         wn--;
  39                         continue;
  40                 }
  41                 if (*s-SA > SB-SA) break;
  42                 c = bittab[*s++-SA];
  43 resume0:
  44                 if (OOB(c,*s)) { s--; break; }
  45                 s++;
  46                 if (c&(1U<<25)) {
  47                         if (*s-0x80u >= 0x40) { s-=2; break; }
  48                         s++;
  49                         if (c&(1U<<19)) {
  50                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  51                                 s++;
  52                         }
  53                 }
  54                 wn--;
  55                 c = 0;
  56         } else for (;;) {
  57                 if (!wn) {
  58                         *src = (const void *)s;
  59                         return wn0;
  60                 }
  61                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  62                         while (wn>=4 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  63                                 *ws++ = *s++;
  64                                 *ws++ = *s++;
  65                                 *ws++ = *s++;
  66                                 *ws++ = *s++;
  67                                 wn -= 4;
  68                         }
  69                 }
  70                 if (*s-1u < 0x7f) {
  71                         *ws++ = *s++;
  72                         wn--;
  73                         continue;
  74                 }
  75                 if (*s-SA > SB-SA) break;
  76                 c = bittab[*s++-SA];
  77 resume:
  78                 if (OOB(c,*s)) { s--; break; }
  79                 c = (c<<6) | *s++-0x80;
  80                 if (c&(1U<<31)) {
  81                         if (*s-0x80u >= 0x40) { s-=2; break; }
  82                         c = (c<<6) | *s++-0x80;
  83                         if (c&(1U<<31)) {
  84                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  85                                 c = (c<<6) | *s++-0x80;
  86                         }
  87                 }
  88                 *ws++ = c;
  89                 wn--;
  90                 c = 0;
  91         }
  92
  93         if (!c && !*s) {
  94                 if (ws) {
  95                         *ws = 0;
  96                         *src = 0;
  97                 }
  98                 return wn0-wn;
  99         }
 100         errno = EILSEQ;
 101         if (ws) *src = (const void *)s;
 102         return -1;
 103 }